Asphalt Pavements

8/3/2019 Asphalt Pavements

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Pavement Surface Condition Field

Rating Manual for Asphalt Pavements

Northwest PavementNorthwest PavementNorthwest PavementNorthwest PavementNorthwest Pavement

Management AssociationManagement AssociationManagement AssociationManagement AssociationManagement Association

Sponsored by:Sponsored by:Sponsored by:Sponsored by:Sponsored by:

Northwest Technology Transfer CenterNorthwest Technology Transfer CenterNorthwest Technology Transfer CenterNorthwest Technology Transfer CenterNorthwest Technology Transfer CenterTransAid Service CenterTransAid Service CenterTransAid Service CenterTransAid Service CenterTransAid Service Center

Washington StateWashington StateWashington StateWashington StateWashington State

Department of TransportationDepartment of TransportationDepartment of TransportationDepartment of TransportationDepartment of Transportation

InspectionProcedureand Guidelin

Flexible Pave

Acknowledgm

RatingConsideratio

Back to L
http://manuals.pdf/


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Pavement Surface Condition FieldRating Manual for Asphalt Pavements

Northwest Pavement Management AssociationNorthwest Pavement Management AssociationNorthwest Pavement Management AssociationNorthwest Pavement Management AssociationNorthwest Pavement Management Association

Sponsored by:Sponsored by:Sponsored by:Sponsored by:Sponsored by:Northwest Technology Transfer CenterNorthwest Technology Transfer CenterNorthwest Technology Transfer CenterNorthwest Technology Transfer CenterNorthwest Technology Transfer Center

TransAid Service CenterTransAid Service CenterTransAid Service CenterTransAid Service CenterTransAid Service Center

Washington StateWashington StateWashington StateWashington StateWashington State

Department of TransportationDepartment of TransportationDepartment of TransportationDepartment of TransportationDepartment of Transportation


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Inspection Procedure and Guidelines 8-9

Rating Considerations 10-13

Flexible Pavement Distresses 14-63

1. Rutting and Wear 14-15

2. Alligator Cracking 16-19Option A Measurement for Alligator Cracking 18

Option B Measurement for Alligator Cracking 19

CONTENTS


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3. Longitudinal Cracking 20-23

Option A Measurement for Longitudinal Cracking 22

Option B Measurement for Longitudinal Cracking 23

4. Nonwheel Path Longitudinal Cracking 24-27

Option A Measurement for Nonwheel PathLongitudinal Cracking 26

Option B Measurement for Nonwheel PathLongitudinal Cracking 27

5. Transverse Cracking 28-31

Option A Measurement for Transverse Cracking 30

Option B Measurement for Transverse Cracking 31

6. Raveling and Aging 32-35

7. Flushing/Bleeding 36-39

8. Patching 40-43

Option A Measurement for Patching 42

Option B Measurement for Patching 42

9. Original WSDOT Patching 44-49


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10. Corrugation and Waves 50-51

Option A Measurement for Corrugationsand Waves 51

Option B - Measurement for Corrugations

and Waves 51

11. Sags and Humps 52-53

Option A Measurement for Sags and Humps 53

Option B Measurement for Sags and Humps 53

12. Block Cracking 54-57

Option A Measurement for Block Cracking 56

Option B Measurement for Block Cracking 56

13. Pavement Edge Condition 58-59

14. Crack Seal Condition 60-63

Acknowledgments to the First Revision 64-67

Acknowledgments to the First Edition 68-69


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8

Inspection Procedure and Guidelines

These inspection procedures offer a method of determining pavement condition through

observing and recording the presence of specific types and severities of defects or

distresses in the pavement surface.

The elements of pavement condition rating are as follows:

1. The type of defect.

2. The severity of the defect.

3. The extent to which the road surface is affected by the defect.

There are several types of defects and several possible severities and extents for each

defect. These are described and illustrated for flexible pavements in the following pages

of this manual.


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Rating Considerations

Listed below are important factors to consider when you collect pavement

condition data.

s Each agency must decide whether to record the extent of the predominant

severity of each defect type or to record the extent ofeach severity of each

defect type. The agency must also decide whether to estimate/measure and

record these extents using finite values or standardized ranges of values.

If thepredominate severityprocedure is used for each type of defect

observed, you should record only one severity, the predominant severity.

Always record the higher rated severity if approximately equal proportions

of more than one severity exist. The purpose is to establish a severity thatrepresents the typical condition of the roadway segment. The extent you

record is always the overall extent associated with all levels of severity for

a given distress type. This extent may be a range of values or it may be a

finite value. Your individual agency may wish to note (in the comments

section of the form) the occurrence of any level of severity that

is significantly higher than what you have recorded in the rating.


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If you are recording the extent associated with each severity of each distress

type, then instead of recording the total extent and the predominant

severity, you will record the extent ofeach severity of each type of defect. It

is recommended that a finite value (the actual percentage or count) of the

extent is recorded for each of the severity categories as use of ranges will

probably result in too large an extent for the total of the severities.s Roads can be rated on foot or by vehicle. In urban areas, rating is frequently

done on foot. The best driving speeds for observing the defects range from 2

to 5 miles per hour. A single lane is generally used, but if time and funds

allow, an agency can measure more than one lane.

Note:Different values will likely be obtained in walking vs. driving and the

agency needs to be aware of possible problems in comparing results

obtained by using more than one technique.

s The relative sun angle and direction of viewing the roadway surface will

greatly affect your visual observation. Be sure to view the pavement from

more than one direction occasionally during the survey to assure the true

nature of the pavement surface is being observed.


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s The time of year and weather (moisture and temperature) conditions over a

given time period can also affect the severity and visibility of certain

distresses. If at all possible, rate the roadway network at a similar time of theyear and only while the pavement is dry.

s When rating a roadway, you must observe the entire area of the traveled

roadway segment or sample and determine the defect severities and extents

over this full pavement surface area.

s When rating composite pavements (such as asphalt over rigid pavement),

classify cracks that may correspond with the concrete joints as distresses and

rate these, and other cracks, as the type of crack they represent (transverse

or longitudinal).

s When rating the width of cracks, use the average width, not the extremes.

Cracks often vary in width and the intent is to rate the overall severity of

the crack.


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s Condition ratings apply only to the traveled surface of a road. Do not include

the conditions of shoulders or other adjacent areas. Shoulder condition,

drainage information, or other items may be accounted for and collected

separately from or with the pavement rating data.

s Areas within the curb returns are considered a part of the intersection for

rating purposes. Intersections are generally rated with a higher functionalclass street or in a given direction. Intersections may also be separately rated

and recorded. Each agency needs to develop its own policy.

s If opposite sides of the roadway or individual lanes are rated separately, use

separate forms and enter the data into the database as separate

multilane segments.

s When any type of defect is not observed, write an N in the first space on

the field form for that defect. The N indicates clearly that a defect was notpresent and reduces the potential for confusion when the data are entered

into the database.

s Your PMS manager may wish you to observe and collect additional

information during the survey. This might include such things as historical

and physical information, documenting new segments, or noting items

needing repair.

s It is important that you receive clear direction from the PMS manager on all

details related to data collection prior to beginning the survey project.


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Flexible Pavement Distresses

1. Rutting and Wear

Rutting is a surface depression within the wheel path. Rutting results from apermanent deformation in any of the pavement layers or subgrades, usually caused

by consolidation or lateral movement of the materials due to traffic loads. When the

upper pavement layers are severely rutted, the pavement along the edges of the

rutted area may be raised. Usually, the rutting occurs gradually across the wheel

path, reaching a maximum depth in the center of the wheel path. Ruts are most

obvious after rainfall when they are full of water.

Wear is surface depression in the wheel path resulting from tire abrasion.


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Measurement for Rutting

Severity: The average rut depth in the wheel path for the segment or sample.

Recommended ranges for estimated severity.

Low 1/4-inch to 1/2-inch

Medium 1/2-inch to 3/4-inch

High over 3/4-inch

Extent: The extent of rutting is assumed to be the full length of the segment in

the wheel path.

Measure: Take measurements in as many locations as is practical and

average them.

Rutting


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2. Alligator Cracking

Alligator fatigue cracking is associated with loads and is usually limited to areas

of repeated traffic loading. The cracks surface initially as a series of parallel

longitudinal cracks within the wheel path that progresses with time and loads to

a more branched pattern that begins to interconnect. The stage at which several

discontinuous longitudinal cracks begin to interconnect, is defined as alligatorcracking. Eventually the cracks interconnect sufficiently to form many pieces,

resembling the pattern of an alligator.

On narrow, two-lane roads, alligator cracking may form along the center line rather

than in the customary wheel paths.

Almost always, the pattern of the cracking (the longer dimension of the connected

cracks) is parallel to the roadway or direction of vehicle travel. However, alligator

cracking occasionally occurs in a pattern transverse to the roadway directionbecause of poor trench compaction, settlement, or frost action.

Pot holes and other occurrences of destroyed or missing pavement are accumulated

as high severity alligator cracking and may also be noted in the comments area of

the field form.


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Severity:

Low Branched, longitudinal, discontinuous thin cracks are

beginning to interconnect and form the typical

alligator pattern with no spalling.

Medium Cracking is completely interconnected and has fullydeveloped an alligator pattern. Some spalling may

appear at the edges of cracks. The cracks may be

greater than 1/4-inch wide, but the pavement pieces

are still in place.

High The pattern of cracking is well developed. Spalling is

very apparent at the crack. Individual pieces may be

loosened and may rock under traffic. Pieces may be

missing. Pumping of fines up through the cracks maybe evident.

Low Medium High


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Option A Measurement for Alligator Cracking

Extent: The extent of alligator cracking is related to the length of wheel paths.

There are two wheel paths in every lane. Therefore, a 100-foot lane

has 200 feet of wheel paths. Accurate measurement and recording as a

percentage of wheel path length is preferable.

Recommended ranges for estimated extent.

1 percent to 9 percent of both wheel paths




Measure: Accumulate the lengths along the surveyed lane of each severity of

the alligator cracking as it occurs in both wheel paths. Divide the

accumulated lengths by twice the length of the segment (two wheelpaths per lane). Multiply by 100 to get percent, and round to a whole

number.


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Option B Measurement for Alligator Cracking

Extent: The extent of alligator cracking is related to the entire survey area.

Measure: Alligator Cracking is measured in square feet. The major difficulty

in measuring this type of distress is that two or three levels of severity

often exist within one distressed area. If these portions can be easily

distinguished from each other, they should be measured and recorded

separately. However, if the different levels of severity cannot be

divided easily, the entire area should be rated at the highest severity

level present.


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3. Longitudinal Cracking

Longitudinal cracks run roughly parallel to the roadway center line. Longitudinal

cracks associated with the beginning of alligator cracking are generally discontinu-

ous, broken, and occur in the wheel path. However, any longitudinal crack that is

clearly within the wheel path should be rated.

Note: Do not include cracks which reside only within 6 inches of a lane edge.

These cracks are assumed to be caused by, or related to, a paving construction joint

and should be rated as nonwheel path longitudinal cracking. If your survey includes

an item for joint or crack seal condition, you should include the seal condition of

these lane edge construction joints in that survey item.


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Severity:

Low The cracks have very little or no spalling along the

edges and are less than 1/4-inch in width. If the cracks

are sealed and the width of the crack prior to sealing is

invisible, they should be classified as Low Severity.

Medium The cracks have little or no spalling but they are greater

than 1/4-inch in width. There may be a few randomly

spaced low severity connecting cracks near the main

crack or at the corners of intersecting cracks.

High Cracks are spalled and there may be several randomly

spaced cracks near the main crack or at the corners of

intersecting cracks. Pieces are visibly missing along the

crack. At some point, this longitudinal crackingbecomes alligator cracking.

Low Medium High


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Option A Measurement for Longitudinal Cracking

Extent: The extent of longitudinal cracking is recorded as a percent of the

length of the surveyed segment.


1 percent to 99 percent of length of segment100 percent to 199 percent of length of segment

200 percent or more of length of segment

Measure: Accumulate the lengths along the surveyed lane of each severity of the

longitudinal cracking as it occurs. Divide the accumulated lengths by

the length of the segment. Multiply by 100 to get percent, and round to

a whole number.


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Option B Measurement for Longitudinal Cracking

Extent: The extent of longitudinal cracking is related to the entire survey area.

Measure: Longitudinal cracks are measured in linear feet. The length and

severity of each crack should be recorded after identification.


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4. Nonwheel Path Longitudinal Cracking

Nonwheel path longitudinal cracks run roughly parallel to the roadway center line.

They may be caused by a poorly constructed paving joint, a reflective crack caused

by joints and cracks beneath the surface course, including joints and cracks near the

edge of the pavement. These types of cracks are not load-associated.

Low severity nonwheel path longitudinal cracking looks very similar to low

severity alligator cracking; however, low severity alligator cracking always occurs

in the wheel path and should be rated as alligator cracking.


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Severity:

Low The cracks have very little or no spalling along the edges

and are less than 1/4-inch in width. If the cracks are

sealed and the width of the crack prior to sealing is


Medium The cracks have little or no spalling but they are greater

than 1/4-inch in width. There may be a few randomly

spaced low severity connecting cracks near the main

crack or at the corners of intersecting cracks.



intersecting cracks. Pieces are visibly missing along the

crack.

Low Medium High


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Extent: The extent of nonwheel path longitudinal cracking is recorded as a

percent of the length of the surveyed segment.


1 percent to 99 percent of length of segment100 percent to 199 percent of length of segment

200 percent or more of length of segment

Measure: Accumulate the lengths along the surveyed lane of each severity

of the nonwheel path longitudinal cracking as it occurs. Divide the

accumulated lengths by the length of the segment. Multiply by 100

to get percent, and round to a whole number.

Option A Measurement for Nonwheel Path Longitudinal Cracking


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Extent: The extent of nonwheel path longitudinal cracking is related to the

entire survey area.

Measure: Nonwheel path longitudinal cracks are measured in linear feet.

The length and severity of each crack should be recorded after

identification.

Option B Measurement for Nonwheel Path Longitudinal Cracking


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5. Transverse Cracking

Transverse cracks run roughly perpendicular to the roadway center line. They may

be caused by surface shrinkage due to low temperatures, hardening of the asphalt,

or cracks in underlying pavement layers such as PCCP slabs. They may extend

partially or fully across the roadway.

Consider only those transverse cracks that are a minimum of two feet in length.


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Severity:

Low The cracks have very little or no spalling along the

edges and are less than 1/4-inch in width. If the cracks

are sealed and the width of the crack prior to sealing is


Medium The cracks have little or no spalling but they aregreater than 1/4-inch in width. There may be a few

randomly spaced low severity connecting cracks near

the main crack or at the corners of intersecting cracks.



intersecting cracks. Pieces are visibly missing along

the crack.

Low Medium High


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Option A Measurement for Transverse Cracking

Extent: The extent of transverse cracking is quantified as a frequency of

occurrence expressed as a count per 100 feet of lane length.


1 to 4 cracks per 100 feet5 to 9 cracks per 100 feet

10 or more cracks per 100 feet

Measure: Accumulate the count along the surveyed lane of each severity of

transverse crack as it occurs. Divide the accumulated counts by the

length of the segment. Multiply by 100 to get the frequency, and

round to a whole number.


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Option B Measurement of Transverse Cracking

Extent: The extent of transverse cracking is related to the entire survey area.

Measure: Transverse cracks are measured in linear feet. The length and severity

of each crack should be recorded after identification.


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6. Raveling and Aging

Raveling and aging are pavement surface deterioration that occurs when aggregate

particles are dislodged (raveling) or oxidation causes loss of the asphalt binder

(aging). An ACP loses its smooth surface and begins to appear very open and

rough.

The severity is rated by the degree of aggregate and binder loss. Rate the overallseverity within the segment as the most predominate observed level.

This distress is measured or observed differently depending on whether the road

surface is BST or ACP.Care should be exercised when rating chip sealed

pavements, as they tend to look raveled because of the inherent nature of the chip

seal surface. However, raveling in chip sealed pavements (loss of aggregate)

actually results in a condition of excess asphalt, and should be rated as flushing

(see next distress, Flushing/Bleeding).


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Severity:

Low The aggregate and/or binder has started to wear

away but has not progressed significantly. The

pavement only appears slightly aged and

slightly rough.

Medium The aggregate and/or binder has worn awayand the surface texture is moderately rough and

pitted. Loose particles may be present, and fine

aggregate is partially missing from the surface.

High The aggregate and/or binder have worn away

significantly, and the surface texture is deeply

pitted and very rough. Fine aggregate is

essentially missing from the surface, and

pitting extends to a depth approaching one half

the coarse aggregate size.

Low Medium High

High


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Extent: The extent of raveling is estimated and expressed relative to the

surface area of the surveyed lane.


Localized Patchy areas, usually in the wheel paths.

Wheel Path Majority of wheel tracks are affected,but little or none elsewhere in the lane.

Entire Lane Most of the lane is affected.

Measure: Estimate the severity and extent.


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7. Flushing/Bleeding

Flushing and bleeding is indicated by an excess of bituminous material on the

pavement surface which presents a shiny, glass-like reflective surface that may

become sticky in hot temperatures.

At the lower severity levels, the extents localized and wheel path may be

difficult to differentiate; however, as the severity increases, wheel path becomesmore well defined. Wheel path refers to tire tracking area and may be used to

represent the condition of only one wheel track being heavily involved.

This distress is measured or observed differently depending on whether the road

surface is BST or ACP. In BST pavements, loss of aggregate (raveling), commonly

referred to as chip loss, leaves the binder exposed. This condition looks like

flushing, and should be rated as flushing.


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Severity:

Low Minor amounts of the aggregate have been covered

by excess asphalt but the condition has not

progressed significantly.

Medium Significant quantities of the surface aggregate have

been covered with excessive asphalt. However, muchof the coarse surface aggregate is exposed, even in

those areas showing flushing.

High Most of the aggregate is covered by excessive asphalt

in the affected area. The area appears wet and is

sticky in hot weather.

Low Medium High


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Extent: The extent of flushing is estimated and expressed relative to the

surface area of the surveyed lane.


Localized Patchy areas, usually in the wheel paths.Wheel Path Majority of wheel tracks are affected, but little or

none elsewhere in the lane.

Entire Lane Most of the lane is affected.

Measure: Estimate the severity and extent.


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8 P t hi


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8. Patching

A patch is an area of pavement which has been replaced with new material to repair

the existing pavement or access the utility.

A patch is considered a defect no matter how well it is performing (a patched area

or adjacent area usually does not perform as well as an original pavement section).

Generally, some roughness is associated with this distress. In general, a patch isless than a typical rehabilitation in size and scope. They are less than full roadway

width and/or are less than project length. Some agencies may have patches as long

as the work defined by another agency as a rehabilitation.

Temporary patches, as well as localized permanent repairs (dig-out repair), are

included in this distress category. Utility cut patches are also included as part of the

patching values.

L P t h h t t l it di t f t


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Medium

Low Patch has at most low severity distress of any type.

Medium Patch has medium severity distress of any type.

High Patch has high severity distress of any type.

Low Medium High

low

Option A Measurement for Patching


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Option A Measurement for Patching

Extent: The extent of patching is related to the length of wheel paths. Each

half of the lane is considered one wheel path.




25 percent or more of both wheel paths.

Option B Measurement for Patching

Extent: The extent of patching is related to the entire survey area.

Measure: Patching is measured in square feet of entire inspection area. No other

distresses (e.g., rutting or cracking) are recorded within a patch. Other

distresses in the patch area are used to determine the severity level of

the patch.


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9 Original WSDOT Patching


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9. Original WSDOT Patching

In general, a patch is less than a typical rehabilitation in size and scope. They are

less than full roadway width and/or are of less than project length. Some agencies

may have patches as long as the work defined by another agency as a rehabilitation.

WSDOT defines a lane with new surfacing as a patch if it is less than about half

a mile in length. Definition of minimum rehabilitation vs. maximum patch length isa matter of agency policy.

Temporary patches, as well as localized permanent repairs (dig-out repair), are

included in this distress category. The patches or repairs which are obviously the

result of utility work are the exception, and are not included as part of the

patching values.

While appropriately done repairs are an asset rather than a liability to the life of a

segment of pavement, the fact that they were required (other than for utility work)

generally indicates some failure in the pavement structure.

If any patch (including a utility patch) shows surface defects, such as alligator

cracking, accumulate those defects also, and include them in the overall

segment rating.


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Patching

Severity: Severity of patching is defined in three categories which are most


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Severity: Severity of patching is defined in three categories which are most

easily recognized by the method of construction.

Low The lowest severity is BST patching or chip seal patching. It

is constructed by spraying hot asphalt onto the roadway

(usually using a truck with a spray bar) and then spreading

and rolling crushed stone onto the surface. It is identified by

its nearly straight edges, rough texture, and surface contours

which mimic the surface below. This is assumed to cover

low severity cracking or raveling.

Medium Blade patching is the medium severity patching. It has edges

shaped to the contours of the surrounding pavement and is of

variable thickness with feathered edges. This type is assumed

to cover (or replace) medium to severe alligator cracking, pot

holes, rutting, or other significant pavement defects. Coldpatches are of this type.

High Dig-Out or Full Depth patching is the most severe of the

types rated. A patch (or repair) of this type is constructed by

neatly cutting out a full depth portion of the pavement,

removing all disturbed materials, and refilling the void with

an appropriate pavement section. This appropriately

reconstructed section should be as strong as the original

pavement section, perhaps even stronger. This type of patchis assumed to replace severe alligator cracking.


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Chip Seal Repair Low Blade Repair Medium Dig Out High

Extent: The extent of patching is related to the length of wheel paths.


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Accurate measurement expressed as a percentage of wheel path

length is preferable. Each half of the lane is considered one wheel

path. This form of measurement is identical to that of alligator

cracking because the general assumption is that patching replaces

alligator cracking.




25 percent or more of both wheel paths

Note: Patching was included in the WSPMS because without a

deduction for patching, a roadway which is virtually made of patches

would appear to be a perfect segment or project. This would result

in the segment or project never being included in a prioritized list ofpavements needing rehabilitation.

If an agency has separate maintenance districts, or crews assigned to

specific areas, the more efficient crew/district can be penalized by the

pavement management system for doing a better job. If its roadways

rate higher as a result of better maintenance operations, those

roadways might not receive repair and rehabilitation funds as a result.

The way in which the PMS uses these distress severities can vary, andthe desired effect can be accommodated by using different deduct

values to reflect the needs of the agency. If patching and/or repairs are

not deemed a serious issue within your agency, then reduce or remove


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the optional local deducts associated with the patching severities.

Measure: Accumulate the lengths along the surveyed lane of each severity

(type) of patching as it occurs in both wheel paths. Divide the

accumulated lengths by twice the length of the segment (two wheelpaths per lane). Multiply by 100 to get percent, and round to a whole

number.

10. Corrugation and Waves


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This distress category covers a general form of surface distress which is not limited

to the wheel path, although they may occur in the wheel path. The distress may

occur in isolated areas, such as at intersections, or it may occur over a large part of

the roadway surface.

Corrugations and waves are regularly occurring transverse undulations in thepavement surface. Corrugations occur as closely spaced ripples, while waves are

undulations whose distance from peak to valley is more than 3 feet.

Severity: The severity of corrugation is defined as the maximum vertical deviation

from a 10-foot straightedge placed on the pavement parallel to the center

line of the roadway.

Low 1/8-inch to 2 inches per 10 feet.

Medium 2 inches to 4 inches per 10 feet.

High Over 4 inches per 10 feet.

Option A Measurement of Corrugation and Waves


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Extent: The extent of corrugations is expressed in percent of the lane

area affected.

1 percent to 9 percent of the area of the segment


25 percent or more of the area of the segment

Measure: Determine severity by measuring the maximum difference in

elevation that occurs within a 10-foot straightedge length centered

over the area of displacement. Rate the overall distress by using the

highest observed level.

Option B Measurement of Corrugation and Waves

Extent: The extent of corrugations is expressed in square feet of the entire

survey area.





11. Sags and Humps


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This distress category also covers forms of surface distress that are not limited to

the wheel path, although they generally include the wheel paths. The distress

usually occurs in isolated areas of the roadway surface.

Sags and humps are localized depressions or elevated areas of the pavement that

result from settlement, pavement shoving, displacement due to subgrade swelling,or displacement due to tree roots.

Severity: The severity of sags or humps, like corrugation, is defined as the maximum

vertical deviation from a 10-foot straightedge placed on the pavement parallel to the

center line of the roadway.

Low 1/8-inch to 2 inches per 10 feet.

Medium 2 inches to 4 inches per 10 feet.

High Over 4 inches per 10 feet.

Option A Measurement for Sags and Humps


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Extent: The extent of sags and humps is expressed in percent of the lane

area affected.



25 percent or more of the area of the segment





Option B Measurement for Sags and Humps

Extent: The extent of sags and humps is expressed in square feet of the entire

survey area.





12. Block Cracking


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Block cracks divide the pavement surface into nearly rectangular pieces with cracks

that intersect at about 90 degrees. This type of distress differs from alligator

cracking in that alligator cracks form smaller, irregular shaped pieces with sharp

angles. Also, alligator cracks are caused by repeated traffic loadings and are,

therefore, generally located in traffic areas (i.e., the wheel paths).

Block cracking is caused principally by shrinkage of the asphalt concrete and daily

temperature cycling. It is not load-associated, although load can increase the

severity of individual cracks. The occurrence of block cracking usually indicates

that the asphalt has hardened significantly through aging. Block cracking normally

occurs over a large portion of the pavement area including nontraffic areas.

However, various fatigue related defects may occur in the same segment.

Severity: The severity of block cracking is defined by the average size of the blocks and the average width of the

cracks that separate them


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cracks that separate them.

Block Size

Low 9 9 feet or greater.

Medium 5 5 feet to 8 8 feet blocks.

High 4 4 feet blocks or less.

Crack Size

Low Less than 1/4 inch.

Medium Over 1/4 inch.

High Spalled.

Option A Measurement of Block Cracking


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Extent: The extent of block cracking is assumed to be the full surveyed

segment. If the block cracking does not extend throughout the

segment, then rate the segment using longitudinal and transverse

cracking.

Measure: Estimate the typical size of the blocks and select the appropriatestandard block size and crack size.

Option B Measurement of Block Cracking

Extent: The extent of block cracking is assumed to be square feet or percent

of length. If the block cracking does not extend throughout the

segment, then rate the segment using longitudinal and transverse

cracking.

Measure: Measure the typical size of the blocks and select the appropriate

standard block size and crack size.


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13. Pavement Edge Condition


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Edge raveling occurs when the pavement edge breaks away from roadways without

curbs or paved shoulders. However, edge conditions can still occur with paved

shoulders. Edge patching is the repair of this condition. The lane less than 10 feet

distress indicates that the edge raveling has progressed to the point where the

pavement width from the center line to the outer edge of roadway has been reduced

to less than 10 feet.

Severity: The severity of Pavement Edge Condition is defined as follows.

Low Edge Raveling

Medium Edge Patching

High Edge lane less than 10 feet.

Measure: Accumulate the lengths along the surveyed lane of

each type edge defect as it occurs. Divide the

accumulated lengths by the length of the segment.

Multiply by 100 to get percent, and round to a

whole number.

Extent: The extent of pavement edge conditions is recorded as a percentage of the length of

the surveyed segment. Recommended ranges for estimated extent.


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Edge Raveling Edge Patching

the surveyed segment. Recommended ranges for estimated extent.

1 percent to 9 percent of the length of the segment

10 percent to 24 percent of the length of the segment

25 percent or more of the length of the segment

14. Crack Seal Condition

R t th diti f i ti k ( j i t) l t Th b t


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Rate the condition of any existing crack (or joint) sealant. There may be separate

information fields available for recording the amount (total length) of seal and the

year it was installed or recording the absence of any sealant on the entire section.

Severity:

None There are no sealed cracks


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None There are no sealed cracks.

Low Sealant in good to excellent condition.

Medium Hairline failure in the sealant allows a minimal amount of

water to pass.

High The sealant is severely cracked and may allow significant

quantities of water to pass. The sealant is wide open (or

nonexistent) and will allow water to pass freely.

Low Medium High

Extent: The extent of crack sealing is quantified as the percent of the total

length of the cracks (or joints) in the segment which exhibit the


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seal condition.

1 percent to 9 percent of the total length of cracks or joints

10 percent to 24 percent of the total length of cracks or joints

25 percent or more of the total length of cracks or joints

Measure: Count (or estimate) and accumulate the length of cracks and joints

that exhibit each severity of seal condition. Count (or estimate) the

total length of cracks and joints in the segment.Divide each of the

accumulated lengths of condition by the total length of cracks and

joints, multiply by 100, and round to a whole number.


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Acknowledgments to the First Revision


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The revision of this manual is the result of cooperation among the members of the Northwest

Pavement Management Association, their respective agencies, the County Road Administra-

tion Board, the Washington State Department of Transportation (WSDOT), and private

industry. The following individuals contributed considerable time and effort in

reviewing drafts.

g

WSDOT

Neal Campbell

John Romero

Linda Pierce

Paul Sachs

Dan Sunde

Cities

Renton John Stein

Bill Wressell

Tacoma Steve Pope

Dan SoderlindVancouver Bill Whitcomb

Counties

Grays Harbor Chuck E Greninger

County Road Administration BoardDave Whitcher


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Grays Harbor Chuck E. Greninger

Island Larry Frostad

Kitsap Callene Abernathy

Lucy Mills

Marion (Oregon) Michael L. Rybka

Joel M. Conder

Skagit Vicki Griffiths

Snohomish Roy Scalf

Randy Firoved

Jim Swearengin

Spokane Lamont Glabb

Thurston Pat Carroll

Private Industry

Measurement Research Corporation Derald Christensen

Pavedex, Inc. Don Meyers

Pavement Engineers, Inc. Didrik A. Voss

In addition, the staffs of the following cities and counties provided valuable

information to assist in the preparation of this manual


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Cities

Airway Heights

Bellevue

Bellingham

Bonney Lake

Bremerton

Edmonds

Ellensburg

Forks

Gig Harbor

Counties

Ada (Idaho)

Adams

Asotin

Benton

Clallam

Columbia

Franklin

Klamath (Oregon)

Okanogan

Pend Oreille

Lacey

Lynden

Moses Lake

Normandy Park

Olympia

Port Angeles

Seattle

Shelton

Spokane

Sunnyside

San Juan

Walla Walla

Whatcom

Whitman

Yakima

Special appreciation is given to Roy Scalf of Snohomish County and Paul Sachs

of the Washington Department of Transportation who provided needed encour-

agement, support, and assistance in bringing this project to a close.


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Acknowledgments to the First Edition


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The development of this manual is the result of cooperation among the members of the

Northwest Pavement Management Systems Users Group, their respective agencies, and the

Washington State Department of Transportation. Members of the Users Group offered many

suggestions and spent many hours in reviewing, critiquing, and commenting on the various

drafts.

Particular appreciation is extended to Derald Christensen of Measurement Research

Corporation for authoring and updating the original series of drafts. Many thanks go to

Randy Firoved, Snohomish County; Scott Radel, City of Bellingham; Butch McGuire,

City of Snohomish; and Steve Pope, City of Tacoma, for their continual participation

and contributions.

Others who contributed considerable effort are:

County Road Administration Board

Association of Washington Cities

University of Washington Transportation Center (TRAC)

Appreciation is extended to Stan Moon, Assistant Secretary for Local Programs

(WSDOT), for his sponsorship and to Keith Anderson, Federal Programs - Research

Office (WSDOT) for coordination of all the details


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Office (WSDOT), for coordination of all the details.

Final editing for compliance with the Washington State Pavement Management System

standards was done by R. Keith Kay, Pavement Management Engineer for WSDOT.


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9902-0177 GC 2,500 4/99


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